This research is designed to quantitate the effects of radiographic contrast media (RCM) and x-ray on three areas of function in cell cultures. 1) What is the effect of RCM on cell uptake of radionuclide nucleic acid and protein precursors, and can this be effected by immediate or more prolonged exposures of the cells to 10 to the minus six dexamthasone. 2) In order to put mutagenic studies in perspective, we plan to evaluate cytogenic effects of RCM using the micronucleus technique and classic chromosone analysis. 3) Using bacterial cultures (Ames Test) and cultured human lymphocytes grown in the presence of bromouridine (Sister Chromatid Exchange) we plan to continue preliminary evaluations of several RCMs in an effort to qualitatively and quantitatively evaluate their mutagenic potential. In addition, drug plus x-ray dose response curves will be generated where appropriate. The techniques used are basic, well characterized cell biology techniques which are currently widely used in studying cell biology in regard to drug toxicity, radiation effects, and mutagenicity. Co-investigators and interdisciplinary consultants who are familiar with these techniques and use them in their everyday work will be available to help the principal investigator fucus these powerful basic tools upon important and as yet unsolved questions in diagnostic radiology.